#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("inline")
#include <bits/stdc++.h>
using namespace std;
#define kien long long
#define pb push_back
#define FOR(i, a, b) for (int i = a;i <= b; i++)
#define FORD(i, a, b) for (int i = a;i >= b; i--)
#define pii pair<int, int>
#define fi first
#define se second
#define dembit(a) __builtin_popcountll(a)
#define task "a"
#define fin(x) freopen(x".inp","r",stdin)
#define fou(x) freopen(x".out","w",stdout)
#define debug(x) cout << x << " ";
#define down cout << "\n"
const kien mod = 1e9 + 7;
const int NTEST = 100;
const int Million = 1e6 + 5;
const int mxn = 2e3 + 5;
mt19937 rd(chrono::high_resolution_clock::now().time_since_epoch().count());
kien rand(kien l, kien r) {
assert(l <= r);
return uniform_int_distribution<kien>(l, r)(rd);
}
kien n, k, m, val[mxn], dem, f[mxn + 5], s[mxn], t[mxn];
kien l, r, sz[mxn], vis[mxn], ans, dp[mxn][mxn][2];
vector <pii> v;
vector <pii> adj[mxn];
void dfs (int u, int pa) {
sz[u] = vis[u] = 1;
dp[u][1][1] = val[u];
for (auto v : adj[u]) {
if (v.fi == pa) continue;
dfs(v.fi, u);
FORD (i, sz[u], 0) FOR (j, 1, min(sz[v.fi], k - i)) {
dp[u][i + j][0] = max(dp[u][i + j][0], dp[u][i][0] + max(dp[v.fi][j][1], dp[v.fi][j][0]));
if (i > 0) dp[u][i + j][1] = max({dp[u][i + j][1], dp[u][i][1] + dp[v.fi][j][0], dp[u][i][1] + dp[v.fi][j][1] + v.se});
}
sz[u] += sz[v.fi];
}
}
void solve() {
cin >> n >> m >> k;
FOR (i, 1, n) {
cin >> s[i] >> t[i];
v.pb({s[i], i}); v.pb({t[i], -i});
}
sort(v.begin(), v.end());
FOR (i, 1, v.size() - 1) {
int len = v[i].fi - v[i - 1].fi;
if (v[i - 1].se > 0 and v[i].se > 0) val[v[i - 1].se] += len;
if (v[i - 1].se < 0 and v[i].se < 0) val[-v[i - 1].se] += len;
if (v[i - 1].se > 0 and v[i].se < 0) {
int x = v[i - 1].se, y = -v[i].se;
if (x == y) { ans += len; continue; }
adj[x].pb({y, len});
adj[y].pb({x, len});
}
if (v[i - 1].se < 0 and v[i].se > 0) ans += len;
}
FOR (i, 1, n) if (!vis[i]) {
dfs(i, 0);
FORD (j, k, 0) {
FOR (z, 1, sz[i]) {
f[j + z] = max(f[j + z], f[j] + max(dp[i][z][0], dp[i][z][1]));
}
}
}
cout << ans + f[k] + m - v[v.size() - 1].fi + v[0].fi;
}
main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
if (fopen(task".inp", "r")) {
fin(task); fou(task);
}
int t = 1; //cin >> t;
while(t--) solve();
cerr << "\n" << 1.0 * clock() / CLOCKS_PER_SEC << "s ";
}
